This invention relates generally to multi-functional apparatuses and more specifically to a multi-functional apparatus for use in an automotive vehicle employing multiple tracks.
Almost all automotive vehicles have a single or a pair of windshield wiper assemblies. These assemblies traditionally include rubber wiper blades mounted upon claw brackets. These claw brackets are pivotably attached to wiper arms mounted upon rotating shafts. The shafts are either directly driven by electric motors or driven by a single electric motor which actuates a series or a parallel-coupled four bar linkage mechanism.
It is common to employ a window wiper assembly for cleaning rear windows of automotive vehicles. Typically, these types of rear window wiper assemblies include a wiper blade mounted upon a bracket which is coupled to a wiper arm. The wiper arm is attached to a wiper shaft rotatably driven in a cyclical oscillating manner by a helical gear. A reversible, fractional horsepower, direct current electric motor serves to actuate the helical gear through an armature shaft-mounted worm gear enmeshed therewith. This type of rear window wiper arrangement is usually mounted upon a pivoting liftgate of a minivan, station wagon, sport-utility vehicle or the like. One such example is disclosed in U.S. Pat. No. 5,519,258 entitled "System and Method for Controlling Vehicle Lift Gate Window Wiper" which issued to Stroven et al. on May 21, 1996.
It is also common in the automotive industry to employ windshield and rear window wiper systems that have an electric motor and a worm gear which are constantly reversing directions in order to oscillate a wiper arm and wiper blade back and forth within a wiping range or path on the window. In other words, the electric motor and worm gear rotate in first respective directions for moving the wiper arm and blade to one side of the window and then reverse directions for moving the wiper arm and blade to the other side of the window. In some situations, the electric motor and worm gear are further rotated to move the wiper arm and blade off of the window to a park position.
These constantly reversing electric motors often suffer from objectionable noise and are prone to a shortened duration due to the longitudinal impact of the ends of the armature shaft against the adjacent bearings and end plug members retaining the armature shaft. These conventional devices also cause a high stress enmeshed condition between the worm gear portion of the armature shaft and the driven worm gear teeth thereby causing gear tooth breakage.
Furthermore, it is known to provide a four-bar linkage to couple a worm gear to a window wiper shaft. In this arrangement, an electric motor and worm gear rotate in a unidirectional manner to facilitate back and forth oscillation of a window wiper arm and blade. In this unidirectional, four-bar linkage construction, a pin always moves concurrently with the worm gear, since the pin is always fixed to the worm gear in a single location. The pin is also coupled to the four-bar linkage. This serves to reduce noise and encourage prolonged life of the electric motor and gears, but has proven difficult to provide a wiper arm and wiper blade park position off of the window. Moreover, the four-bar linkage cannot remain stationary if the worm gear is rotated. Such an arrangement is disclosed in U.S. Pat. No. 5,182,957 entitled "Drive Unit, in Particular for a Windshield Wiper System on a Motor Vehicle" which issued to Bohmer et al. on Feb. 2, 1993.
It is also known to provide a window wiper construction having an electric motor and a worm gear with a continuous and closed loop cam track. A pin connected to a drive pawl rides in the cam track. In one position, the pin of the drive pawl is cammed from engagement with a shoulder of the cam track so as to interrupt the driving connection between an output shaft coupled to the wiper and the worm gear. Such an arrangement is disclosed in U.S. Pat. No. 3,688,332 entitled "Mechanism for Opening and Closing a Cover for a Concealed Wiper System" which issued to Bellware on Sep. 5, 1972. Notwithstanding, this device appears to be overly complex. It also requires a large number of parts which adds undue expense. Moreover, disengagement of the drive pawl from the cam track can cause reengagement difficulties due to tolerance mismatches of parts or due to operation of the device on a bumpy road.
Some conventional vehicles also provide a rear window release lock or latch, actuated by a solenoid, which can be unlocked to allow for upward pivotal movement of a rear window in relation to the otherwise stationary liftgate. In combination therewith, a separate liftgate lock is often mounted upon the liftgate door for fastening the liftgate to the body thereby preventing inadvertent pivotal opening. This liftgate lock is traditionally operated by manual key or handle rotation, or through a separate electric motor or solenoid.
Separate motors or solenoids are commonly required to actuate these various locks and the wiper. The traditional need for such a multiplicity of electromagnetic devices has increased the automotive vehicle weight and cost while further proving difficult to package within the often small spaces provided. This added weight is especially detrimental when the window wiper mechanism, rear window lock and liftgate lock, as well as their distinct respective electromagnetic devices, are all incorporated within the pivoting liftgate. Not only is the piece cost increased due to this multiplicity of electromagnetic devices, but the assembly cost, part number proliferation and handling costs, electric wiring costs, objectional motor noise, and failure modes are increased.
Furthermore, U.S. Pat. No. 3,688,332 which issued to Bellware, as set forth above, discloses a windshield wiper device that further employed levers and pivot pins to open and close a cover. More recently, WO 96/33891 entitled "Multi-Functional Apparatus Employing an Intermittent Motion Mechanism," WO 96/33893 entitled "Multi-Functional Apparatus Employing an Electromagnetic Device," and WO 96/33892 entitled "Control System for an Automotive Vehicle Multi-Functional Apparatus," all of which were published on Oct. 31, 1996, disclose a significantly improved system wherein a single electromagnetic device can selectively operate intermittent motion mechanisms coupled to a window wiper, a door lock, a window release lock and the like. Notwithstanding, these devices require further refinement and improvement. For example, if the window wiper is frozen onto a window, a door could not be unlocked with the geneva and starwheel mechanism constructions. Moreover, a car wash or bumpy road could cause the window wiper to undesirably and destructively move from its parked position when a wiper clutch is disengaged, for the split-shaft clutch construction. The split-shaft clutch embodiment also requires further improvements and refinements to increase the durability and robustness of design, while further minimizing the weight of the unit.